Armstrong furnace 8 flashes: Rollout switch open
Eight flashes means a rollout switch opened. Flame came forward out of the burner compartment instead of being drawn into the heat exchanger. This is the most serious code on the control.
Applies to: Allied Air Enterprises A80UH1E and 80G1UHE gas furnaces with the -02 integrated control, sold as Armstrong Air, AirEase, Concord and Ducane.
What it means
Rollout switches sit on or near the burner assembly and open when they detect heat where there should be none. They exist to catch flame rollout — flame escaping forward out of the burner box rather than being pulled through the heat exchanger by the draft. Rollout means the combustion path is obstructed or the draft has failed. It can scorch wiring, damage the furnace, and produce carbon monoxide. Unlike the limit switches, which reset themselves once things cool, a rollout switch is manual reset: it stays tripped until someone physically presses it. That is deliberate, so that a person has to attend the furnace and establish why before it runs again.
Most common causes
- A blocked or restricted heat exchanger, so combustion gases cannot pass through it.
- A blocked or partly blocked flue, forcing combustion products back toward the burners.
- A failed or weak draft inducer not pulling flame into the heat exchanger.
- A cracked heat exchanger disturbing the combustion airflow.
- Burners that are dirty, misaligned or partly blocked.
- Insufficient combustion air in a confined furnace space.
- Overfiring, with gas pressure set too high for the burners.
How to diagnose it
- Treat this as a stop-and-call fault rather than something to work through. Its causes are dominated by conditions that produce carbon monoxide.
- Check that carbon monoxide alarms are present and working. If any has sounded, leave and call the fire service from outside.
- Look for visible scorching, soot or melted wire insulation near the burner compartment — from outside, without dismantling anything.
- Note whether the flue or vent termination is obviously blocked.
- Note that this control gives rollout its own code, so eight flashes is unambiguous — it is not sharing a count with anything less serious.
How to fix it
- Turn the furnace off at its service switch and call a licensed heating technician.
- Do not press the rollout switch reset button to restart the furnace. It tripped because flame went somewhere it should not, and resetting without finding out why puts the furnace straight back into that condition.
- Have working carbon monoxide alarms on every level of the home and outside each sleeping area, which is what NFPA and CPSC guidance call for.
- Every underlying cause — heat exchanger, flue, inducer, burners, gas pressure — is licensed work. There is no homeowner portion of this repair.
Notes
The manual reset on a rollout switch is the clearest signal a furnace gives about how seriously to take a fault. Every other common safety resets itself; this one requires a person, precisely so the condition gets investigated rather than cycled through.
Related
- 7 flashes — Primary or secondary limit open
- 12 flashes — Flame sensed without the gas valve energised
All codes for this manufacturer
Armstrong Air, AirEase, Concord and Ducane furnace codes — every code, with what differs between models.
Not sure this is your brand?
The same count means something else on other furnaces. What 8 flashes means on every brand puts them side by side.